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
@@ -433,6 +433,7 @@
 }
 
 Error DWARFYAML::emitDebugLine(raw_ostream &OS, const DWARFYAML::Data &DI) {
+  uint64_t LineTableIndex = 0;
   for (const auto &LineTable : DI.DebugLines) {
     writeInitialLength(LineTable.Format, LineTable.Length, OS,
                        DI.IsLittleEndian);
@@ -461,6 +462,10 @@
       emitFileEntry(OS, File);
     OS.write('\0');
 
+    uint8_t AddrSize = DI.Is64BitAddrSize ? 8 : 4;
+    if (DI.CompileUnits.size() > LineTableIndex)
+      AddrSize = DI.CompileUnits[LineTableIndex++].AddrSize;
+
     for (auto Op : LineTable.Opcodes) {
       writeInteger((uint8_t)Op.Opcode, OS, DI.IsLittleEndian);
       if (Op.Opcode == 0) {
@@ -470,8 +475,9 @@
         case dwarf::DW_LNE_set_address:
         case dwarf::DW_LNE_set_discriminator:
           // TODO: Test this error.
-          if (Error Err = writeVariableSizedInteger(
-                  Op.Data, DI.CompileUnits[0].AddrSize, OS, DI.IsLittleEndian))
+          // FIXME: The operands of set_discriminator is not an address.
+          if (Error Err = writeVariableSizedInteger(Op.Data, AddrSize, OS,
+                                                    DI.IsLittleEndian))
             return Err;
           break;
         case dwarf::DW_LNE_define_file:
diff --git a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-line.yaml b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-line.yaml
--- a/llvm/test/tools/yaml2obj/ELF/DWARF/debug-line.yaml
+++ b/llvm/test/tools/yaml2obj/ELF/DWARF/debug-line.yaml
@@ -317,3 +317,90 @@
       IncludeDirs:           []
       Files:                 []
       Opcodes:               []
+
+## h) Test that if the line table has an associated compilation unit, yaml2obj will use the address size
+## of the compilation unit's otherwise yaml2obj will infer it from the object file.
+
+# RUN: yaml2obj --docnum=8 %s -o %t8.o
+# RUN: llvm-readelf --hex-dump=.debug_line %t8.o | FileCheck %s --check-prefix=ADDRSIZE
+
+#      ADDRSIZE: Hex dump of section '.debug_line':
+# ADDRSIZE-NEXT: 0x00000000 34120000 02003412 00000101 010e0d00 4.....4.........
+##                          ^-------                            unit_length (4-byte)
+##                                   ^---                       version (2-byte)
+##                                       ^--------              header_length (4-byte)
+##                                                ^-            minimum_instruction_length (1-byte)
+##                                                  ^-          default_is_stmt (1-byte)
+##                                                     ^-       line_base (1-byte)
+##                                                       ^-     line_range (1-byte)
+##                                                         ^-   opcode_base (1-byte)
+##                                                           ^- null byte for terminating include_directories
+# ADDRSIZE-NEXT: 0x00000010 00000902 78563412 34120000 02003412 ....xV4.4.....4.
+##                          ^-                                  null byte for terminating file_names
+##                            ^-                                DW_LNS_extended_op
+##                              ^-                              extended op length (ULEB128) 0x09
+##                                ^-                            DW_LNE_set_address
+##                                   ^-------                   address (4-byte)
+##                                            ^-------          unit_length (4-byte)
+##                                                     ^---     version (2-byte)
+##                                                         ^--- header_length (4-byte)
+# ADDRSIZE-NEXT: 0x00000020 00000101 010e0d00 00000902 efcdab90 ................
+##                          ----
+##                              ^-                              minimum_instruction_length (1-byte)
+##                                ^-                            default_is_stmt (1-byte)
+##                                   ^-                         line_base (1-byte)
+##                                     ^-                       line_range (1-byte)
+##                                       ^-                     opcode_base (1-byte)
+##                                         ^-                   null byte for terminating include_directories
+##                                            ^-                null byte for terminating file_names
+##                                              ^-              DW_LNS_extended_op
+##                                                ^-            extended op length (ULEB128) 0x09
+##                                                  ^-          DW_LNE_set_address
+##                                                     ^------- address (8-byte)
+# ADDRSIZE-NEXT: 0x00000030 78563412                            xV4.
+##                          --------
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+DWARF:
+  debug_info:
+    - Version:    4
+      AbbrOffset: 0x00
+      AddrSize:   0x04
+  debug_line:
+    - Length:                0x1234
+      Version:               2
+      PrologueLength:        0x1234
+      MinInstLength:         1
+      DefaultIsStmt:         1
+      LineBase:              1
+      LineRange:             14
+      OpcodeBase:            13
+      StandardOpcodeLengths: []
+      IncludeDirs:           []
+      Files:                 []
+      Opcodes:
+        - Opcode:          DW_LNS_extended_op
+          ExtLen:          9
+          SubOpcode:       DW_LNE_set_address
+          Data:            0x12345678
+    - Length:                0x1234
+      Version:               2
+      PrologueLength:        0x1234
+      MinInstLength:         1
+      DefaultIsStmt:         1
+      LineBase:              1
+      LineRange:             14
+      OpcodeBase:            13
+      StandardOpcodeLengths: []
+      IncludeDirs:           []
+      Files:                 []
+      Opcodes:
+        - Opcode:          DW_LNS_extended_op
+          ExtLen:          9
+          SubOpcode:       DW_LNE_set_address
+          Data:            0x1234567890abcdef