Don't require a null terminator when loading objects

When a null terminator is required and the file size is a multiple of the system page size, MemoryBuffer will prefer pread() over mmap(), which can result in excessive memory usage.

Patch by Mike Hommey!

Differential Revision: https://reviews.llvm.org/D56475

llvm-svn: 350774

llvm/lib/Object/Binary.cpp

@@ -88,7 +88,8 @@ Expected<std::unique_ptr<Binary>> object::createBinary(MemoryBufferRef Buffer,
 
 Expected<OwningBinary<Binary>> object::createBinary(StringRef Path) {
   ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
-      MemoryBuffer::getFileOrSTDIN(Path);
+      MemoryBuffer::getFileOrSTDIN(Path, /*FileSize=*/-1,
+                                   /*RequiresNullTerminator=*/false);
   if (std::error_code EC = FileOrErr.getError())
     return errorCodeToError(EC);
   std::unique_ptr<MemoryBuffer> &Buffer = FileOrErr.get();