[JITLink] Silence a narrowing conversion warning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358821 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/ExecutionEngine/JITLink/JITLink.h b/include/llvm/ExecutionEngine/JITLink/JITLink.h
index 1c9f7ef..cc4149a 100644
--- a/include/llvm/ExecutionEngine/JITLink/JITLink.h
+++ b/include/llvm/ExecutionEngine/JITLink/JITLink.h
@@ -381,7 +381,7 @@
     assert(!Parent.isZeroFill() && "Trying to get content for zero-fill atom");
     assert(Size <= std::numeric_limits<size_t>::max() &&
            "Content size too large");
-    return {ContentPtr, Size};
+    return {ContentPtr, static_cast<size_t>(Size)};
   }
   void setContent(StringRef Content) {
     assert(!Parent.isZeroFill() && "Calling setContent on zero-fill atom?");