From 11550c1deb60de3e30ce5866d0c5c2aa0f3dbf8a Mon Sep 17 00:00:00 2001
From: Brian Gaeke <gaeke@uiuc.edu>
Date: Fri, 23 Apr 2004 17:38:17 +0000
Subject: [PATCH] mmap of a zero length file returns null on some platforms, so
 hack around it.

llvm-svn: 13121
---
 llvm/utils/fpcmp/fpcmp.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/llvm/utils/fpcmp/fpcmp.cpp b/llvm/utils/fpcmp/fpcmp.cpp
index 6f8298e5c78b..7e472d474f67 100644
--- a/llvm/utils/fpcmp/fpcmp.cpp
+++ b/llvm/utils/fpcmp/fpcmp.cpp
@@ -50,6 +50,12 @@ static void OpenFile(const std::string &Filename, unsigned &Len, char* &BufPtr){
     std::cerr << "Error: cannot open file '" << Filename << "'\n";
     exit(2);
   }
+
+  // If mmap decided that the files were empty, it might have returned a
+  // null pointer. If so, make a new, fake pointer -- it shouldn't matter
+  // what it contains, because Len is 0, and it should never be read.
+  if (BufPtr == 0 && Len == 0)
+    BufPtr = new char[1];
 }
 
 static bool isNumberChar(char C) {