diff --git a/llvm/tools/llvm-readobj/Error.cpp b/llvm/tools/llvm-readobj/Error.cpp
index 7e6f780..492eb33 100644
--- a/llvm/tools/llvm-readobj/Error.cpp
+++ b/llvm/tools/llvm-readobj/Error.cpp
@@ -17,6 +17,9 @@
 using namespace llvm;
 
 namespace {
+// FIXME: This class is only here to support the transition to llvm::Error. It
+// will be removed once this transition is complete. Clients should prefer to
+// deal with the Error value directly, rather than converting to error_code.
 class _readobj_error_category : public std::error_category {
 public:
   const char* name() const LLVM_NOEXCEPT override;