diff --git a/lib/TableGen/TableGenBackend.cpp b/lib/TableGen/TableGenBackend.cpp
index 7c8367ab9df..79d567753a6 100644
--- a/lib/TableGen/TableGenBackend.cpp
+++ b/lib/TableGen/TableGenBackend.cpp
@@ -14,13 +14,20 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TableGen/TableGenBackend.h"
+#include <algorithm>
+
 using namespace llvm;
 
+const size_t MAX_LINE_LEN = 80U;
+
 static void printLine(raw_ostream &OS, const Twine &Prefix, char Fill,
                       StringRef Suffix) {
-  uint64_t Pos = OS.tell();
+  size_t Pos = (size_t)OS.tell();
+  assert((MAX_LINE_LEN - Prefix.str().size() - Suffix.size() > 0) &&
+    "header line exceeds max limit");
   OS << Prefix;
-  for (unsigned i = OS.tell() - Pos, e = 80 - Suffix.size(); i != e; ++i)
+  const size_t e = MAX_LINE_LEN - Suffix.size();
+  for (size_t i = (size_t)OS.tell() - Pos; i < e; ++i)
     OS << Fill;
   OS << Suffix << '\n';
 }
@@ -28,10 +35,22 @@ static void printLine(raw_ostream &OS, const Twine &Prefix, char Fill,
 void llvm::emitSourceFileHeader(StringRef Desc, raw_ostream &OS) {
   printLine(OS, "/*===- TableGen'erated file ", '-', "*- C++ -*-===*\\");
   printLine(OS, "|*", ' ', "*|");
-  printLine(OS, "|* " + Desc, ' ', "*|");
-  printLine(OS, "|*", ' ', "*|");
-  printLine(OS, "|* Automatically generated file, do not edit!", ' ', "*|");
-  printLine(OS, "|*", ' ', "*|");
+  size_t Pos = 0U;
+  size_t PosE;
+  StringRef Prefix("|*");
+  StringRef Suffix(" *|");
+  do{
+    size_t PSLen = Suffix.size() + Prefix.size();
+    PosE = Pos + ((MAX_LINE_LEN > (Desc.size() - PSLen)) ?
+      Desc.size() :
+      MAX_LINE_LEN - PSLen);
+    printLine(OS, Prefix + Desc.slice(Pos, PosE), ' ', Suffix);
+    Pos = PosE;
+  } while(Pos < Desc.size());
+  printLine(OS, Prefix, ' ', Suffix);
+  printLine(OS, Prefix + " Automatically generated file, do not edit!", ' ',
+    Suffix);
+  printLine(OS, Prefix, ' ', Suffix);
   printLine(OS, "\\*===", '-', "===*/");
   OS << '\n';
 }