1 files changed, 7 insertions, 20 deletions

diff --git a/contrib/llvm-project/llvm/lib/Support/MemoryBuffer.cpp b/contrib/llvm-project/llvm/lib/Support/MemoryBuffer.cpp
index d3fa3c6f065d..7816779cca1d 100644
--- a/contrib/llvm-project/llvm/lib/Support/MemoryBuffer.cpp
+++ b/contrib/llvm-project/llvm/lib/Support/MemoryBuffer.cpp
@@ -14,16 +14,15 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Config/config.h"
 #include "llvm/Support/AutoConvert.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Errc.h"
-#include "llvm/Support/Errno.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MathExtras.h"
-#include "llvm/Support/Path.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/SmallVectorMemoryBuffer.h"
 #include <cassert>
-#include <cerrno>
 #include <cstring>
 #include <new>
 #include <sys/types.h>
@@ -220,28 +219,16 @@ public:
   MemoryBuffer::BufferKind getBufferKind() const override {
     return MemoryBuffer::MemoryBuffer_MMap;
   }
+
+  void dontNeedIfMmap() override { MFR.dontNeed(); }
 };
 } // namespace
 
 static ErrorOr<std::unique_ptr<WritableMemoryBuffer>>
 getMemoryBufferForStream(sys::fs::file_t FD, const Twine &BufferName) {
-  const ssize_t ChunkSize = 4096*4;
-  SmallString<ChunkSize> Buffer;
-
-  // Read into Buffer until we hit EOF.
-  size_t Size = Buffer.size();
-  for (;;) {
-    Buffer.resize_for_overwrite(Size + ChunkSize);
-    Expected<size_t> ReadBytes = sys::fs::readNativeFile(
-        FD, makeMutableArrayRef(Buffer.begin() + Size, ChunkSize));
-    if (!ReadBytes)
-      return errorToErrorCode(ReadBytes.takeError());
-    if (*ReadBytes == 0)
-      break;
-    Size += *ReadBytes;
-  }
-  Buffer.truncate(Size);
-
+  SmallString<sys::fs::DefaultReadChunkSize> Buffer;
+  if (Error E = sys::fs::readNativeFileToEOF(FD, Buffer))
+    return errorToErrorCode(std::move(E));
   return getMemBufferCopyImpl(Buffer, BufferName);
 }