diff --git a/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.h b/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.h
--- a/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.h
+++ b/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.h
@@ -214,6 +214,9 @@
   void writeProloguePayload(const DWARFDebugLine::Prologue &Prologue,
                             AsmPrinter &Asm) const;
 
+  // Calculate the number of bytes the Contents will take up.
+  size_t getContentsSize() const;
+
   llvm::Optional<DWARFDebugLine::Prologue> Prologue;
   std::vector<ValueAndLength> CustomPrologue;
   std::vector<ValueAndLength> Contents;
diff --git a/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp b/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp
--- a/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp
+++ b/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp
@@ -27,6 +27,7 @@
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCTargetOptionsCommandFlags.inc"
 #include "llvm/PassAnalysisSupport.h"
+#include "llvm/Support/LEB128.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
@@ -175,7 +176,7 @@
     P.TotalLength += 4;
     P.FormParams.Format = DWARF64;
   }
-  P.TotalLength += Contents.size();
+  P.TotalLength += getContentsSize();
   P.FormParams.Version = Version;
   P.MinInstLength = 1;
   P.MaxOpsPerInst = 1;
@@ -259,6 +260,24 @@
   }
 }
 
+size_t dwarfgen::LineTable::getContentsSize() const {
+  size_t Size = 0;
+  for (auto Entry : Contents) {
+    switch (Entry.Length) {
+    case ULEB:
+      Size += getULEB128Size(Entry.Value);
+      break;
+    case SLEB:
+      Size += getSLEB128Size(Entry.Value);
+      break;
+    default:
+      Size += Entry.Length;
+      break;
+    }
+  }
+  return Size;
+}
+
 MCSymbol *dwarfgen::LineTable::writeDefaultPrologue(AsmPrinter &Asm) const {
   MCSymbol *UnitStart = Asm.createTempSymbol("line_unit_start");
   MCSymbol *UnitEnd = Asm.createTempSymbol("line_unit_end");