Support/MemoryBuffer: Replace all uses of std::string *ErrMsg with error_code &ec. And fix clients.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121379 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/CommandLine.cpp b/lib/Support/CommandLine.cpp
index a99e46d..e856509 100644
--- a/lib/Support/CommandLine.cpp
+++ b/lib/Support/CommandLine.cpp
@@ -22,6 +22,7 @@
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/system_error.h"
 #include "llvm/Target/TargetRegistry.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/Path.h"
@@ -464,8 +465,9 @@
       if (FileStat && FileStat->getSize() != 0) {
 
         // Mmap the response file into memory.
+        error_code ec;
         OwningPtr<MemoryBuffer>
-          respFilePtr(MemoryBuffer::getFile(respFile.c_str()));
+          respFilePtr(MemoryBuffer::getFile(respFile.c_str(), ec));
 
         // If we could open the file, parse its contents, otherwise
         // pass the @file option verbatim.